1. Field of the Invention
The present invention relates to an electrodeless lighting system and, more particularly, to an electrodeless lighting system capable of heightening a light efficiency by concentrating microwave to an electrodeless plasma bulb positioned inside a resonator.
2. Description of the Background Art
In general, a light system using microwave is a device radiating visible ray or ultraviolet ray by applying a microwave energy to an electrodeless plasma bulb, of which a lamp has a long life span compared to a general incandescent electric lamp or a fluorescent lamp and excellent illumination effect.
FIG. 1 is a vertical-sectional view showing a lighting system using microwave energy in accordance with a conventional art.
As shown in FIG. 1, the conventional lighting system using microwave energy includes: a case 1 forming a predetermined internal space; a magnetron 2 mounted inside the case 1 and generating microwave; a high voltage generator 3 increasing general AC power to a high voltage and supplying it to the magnetron 2; a waveguide 4 for guiding microwave generated from the magnetron 2; a resonator 6 installed at an outlet of the waveguide 4, communicating with the waveguide 4, and preventing leakage of microwave while allowing light to pass therethrough; and a bulb 5 positioned inside the resonator 6 and generating light as an enclosed material becomes plasma by a microwave energy transmitted through the waveguide 4.
The lighting system using microwave also includes a reflection mirror 7 formed at a front side of the case land a neighboring region of the resonator 6, to concentratively reflect light generated from the bulb 5 forwardly.
A dielectric mirror 8 is installed in the outlet 4a of the waveguide 4 to allow microwave transmitted through the waveguide to pass therethrough and light emitted from the bulb 5 to be reflected forwardly, and a hole 8a is formed at the center of the dielectric mirror 8 to allow an shaft part 9 of the bulb 5 to penetrate therethrough.
A cooling fan assembly 10 for cooling the magnetron 2 and the high voltage generator 3 is provided at a rear side of the case 1.
Reference numeral 10a denotes a fan housing, 10b denotes a blowing fan, M1 denotes a bulb motor, and M2 denotes a fan motor.
The conventional lighting system using microwave is operated as follows.
When a drive signal is inputted to the high voltage generator 3, the high voltage generator 3 increases AC power and supplies the increased high voltage to the magnetron 2. Then, oscillated by the high voltage, the magnetron 2 generates microwave having a very high frequency. The thusly generated microwave is guided through the waveguide 4 and radiated into the resonator 6 through a slot part 4b formed at the inner side of the outlet 4a of the waveguide. 4 discharges a material enclosed in the bulb 5 to generate light having a specific spectrum, and as light is reflected forwardly by the reflection mirror 7 and the dielectric mirror 8, the illuminated space becomes bright.
However, the conventional electrodeless lighting system has the following problem.
That is, since microwave introduced into the resonator through the waveguide is not concentrated around the bulb but spread out, failing to form a strong electric field. This makes the bulb unstable in its initial lighting and a radiation efficiency of the bulb is degraded.